most efficient speed ? Prius C

If you seek to absolutely maximize mpg, search on the keyword "hypermiling" and you'll find much discussion. The relevant factors are general driving habits rather than speed alone. To post one example, here is a YouTube clip of a guy driving a loop for about 25 minutes and achieving 65 mpg as he explains his technique.

 

I would guess that the 'c' should be similar to the Liftback in this regard. For the later, with all accessories off, most fuel efficient constant speed is roughly 15 mph, or about 25 kph.

See Updated MPG vs MPH chart for a nice chart that goes down to only 25 mph. The 15 mph peak is found in other discussions.

 

You can get 60 mpg going 50-55 mph. i get about 42 mpg going 70 mph and 46-50 going 65.

any speed under 50 mph will get you over 75 mpg.

Just based off my driving.

 

Pedal pressure or throttle position is more effective in finding the most efficient speed because 40 mph on a flat may be most efficient but roads are not always flat. Most efficient speed is putting the HSI bar at just beyond the halfway mark.

 

What James said.

 

YMMV due to wind speed, wind direction, incline, decline, tire pressure, engine temp, heat/ac setting, fan setting, windows up, windows down, number of passengers, whether passengers have eaten lately, dog/cat ratio, moon phase, and even altitude/gravity point. There is not one speed that is best, there is one speed that is best for RIGHT NOW. You may or may not be anywhere near it.


But I do keep seeing 37 mph a lot...

 

Don't forget: if you are in a different color car the speed changes as well.

 

Drove down into Arkansas this morning, 74 miles. 62 mpg. Drove home, slower, 57 mpg. Wind hit me coming home. With an instant MPG gauge one can fine tune speed to best MPG. I can bump cruise up or down til I get what is best and stay close to speed limit. Not unusual to increase the speed a little to improve the mileage.
Dan

 

i drove through Arkansas' mountains to Louisiana...the highway was just going straight down. no gas required lol.

 

0!

 

On the highway where you need to keep up with traffic I try to keep at 65 or below, but 63 mph seems to be a magic number for highway milesage for me.

 

Your profile says you are in Melbourne which with your relatively flat and straight roads should be a great city to Pulse & Glide in where traffic permits. There are a few videos (and LOTS of threads) about this technique that are well worth watching and reading, just Google for them and they'll come up. You have to unlearn what you've always been told about fuel efficiency in a traditional car and replace it with what you'll be learning. This is going to be the biggest impact thing you can do.

Second to that, make sure your tyre pressure is right. Toyota puts 220 kPa (32 psi) for all wheels on the placard (in Australia), but you'll get better economy going above this. This is a compromise so you don't want to go too high as you will impact ride firmness and if you overdo it, it can be detrimental to stopping distance.. Many on these forums talk of 40 psi... I've been using 36 but I'm planning to try a bit higher.

Otherwise I'd kind of concur with what the others are saying... going above 80-90km/h is going to noticably harm your fuel economy. Slowing it down should improve it.

 

Any speed under 50 will provide 75mpg? I only wished that is what I got! LOL

Granted, I'm sure you can get 70mpg hypermiling, but if you're in city traffic where you have to step on the gas a little more to go with the flow of traffic, I'm finding 55mpg my average, roughly speaking.

In terms of what "speed" is best, I think its a safe assumption that up to 50mph is your sweet spot, but once you get over the 50mph highway speed rating, each mile faster will begin to significantly reduce mileage.

Although I just drove from Rochester to Buffalo yesterday (a 65 mile range) and averaged 53mpg going 70 mph. So I didn't suffer quite the loss in efficiency as was discussed here. And I also filled up my tank with ethanol free fuel last time I refilled, which helps add 1-2mpg.

 

Was a bit early getting to where I was going tonight so I just went for a fun drive... wasn't even thinking about driving efficiently (though I guess I do now habitually). I love how effortlessly the car posts the numbers cruising around at city speeds. NB. This was off a completely warm start after a short stop.


65.3 MPG, Average 19 mph, EV distance 9.26 miles, 59°F.

Only thing is - I noticed a discrepancy between this data and that recorded by the built-in GPS:



I took this two minutes later, yes, but the start time is right. So what does the car mean by "Driving Time" on the MFD? I may have to take my GPS data logger next time to compare logs with the built-in GPS.

Later on in the evening I realised an elevation profile was probably in order. The red line indicates where I was when I took the above images.

 

Elevation profile?... My car doesn't have that...

 

I agree with 45-55 mph.

 

I say 40 MPH because the EV works under 43 MPH